Fly fishing requires three major pieces of equipment: a fly fishing rod, a reel and a line. The line, which normally consists of a backing segment, a fly line segment and a leader segment, is retained upon the reel which is in turn retained upon the fly rod. The line is strung through the fly rod and a fly attached to the end of the leader. The weight of the fly line and the properties of the fly rod are then used to cast the fly line and hence the fly to a desired location with a desired presentation in hopes of catching a fish. Each piece of equipment is required to perform several tasks to catch a fish.
A fly fishing reel retains the fly line in orderly coils on a spool when the equipment is not in use. The fly line may take a memory set if it is coiled on a small diameter arbor.
Additionally, a reel must provide drag. Drag is tension or resistance applied to the line when a fish takes the fly and tries to swim away. Most modern reels provide variable drag resistance. When a fly fisher uses a light leader and tippet, a light drag must be used or the fish will break the line and escape. A drag must apply resistance in the "line out" direction but should not apply any resistance in the "line in" direction. One sometimes needs to reel in quickly to avoid slack as a fish swims toward one. When the line is slack, control of the fish is lost. The fish may tangle the line or apply a shock to the tippet/leader, snapping it.
The "line out" and "line in" directions are not generally fixed with respect to reel products. This is because some fly fishers prefer to retrieve line with their left hand while other fly fishers prefer to retrieve line using their right hand. Reeks must therefore be capable of in effect interchanging the line in/line out directions.
Additionally, it is sometimes desirable to change line when fishing. One mechanism for doing this is to supply additional spools with a reel. The fly fisher stores different kinds of line on the different spools and then interchanges the spools on the reel. Thus, line changes in the field are facilitated.
The above-described problems and design issues are amplified in the salt water environment. When one is fishing in salt water, one is usually seeking larger, stronger fish. One is using heavier tackle in a more corrosive environment.
Over the last few years, large arbor reels have appeared. These reels have spools with large, central arbors and two side walls. The large arbors allow a spool to accommodate larger coils of line while minimizing the weight for the size of coils. However, numerous problems still exist. Changing spools often involves removing more parts than the spool itself. Parts can be lost or damaged. Drag mechanisms are sometimes less than ideal. Switching a reel from right-hand retrieve to left-hand retrieve can be complicated and/or difficult. Some reels cannot withstand the rapid, forceful line draw of a strong, fast saltwater game fish. An improved reel is needed.